FIX: Do not show duplicate_link notice for quotes (#12481)

Quoting a link from the topic would show a false duplicate_link notice.

app/assets/javascripts/discourse/app/controllers/composer.js

@@ -453,8 +453,25 @@ export default Controller.extend({
       const post = this.get("model.post");
       const $links = $("a[href]", $preview);
       $links.each((idx, l) => {
-        const href = $(l).prop("href");
+        const href = l.href;
         if (href && href.length) {
+          // skip links in quotes
+          for (let element = l; element; element = element.parentElement) {
+            if (
+              element.tagName === "DIV" &&
+              element.classList.contains("d-editor-preview")
+            ) {
+              break;
+            }
+
+            if (
+              element.tagName === "ASIDE" &&
+              element.classList.contains("quote")
+            ) {
+              return true;
+            }
+          }
+
           const [warn, info] = linkLookup.check(post, href);
 
           if (warn) {

app/assets/javascripts/discourse/tests/acceptance/composer-test.js

@@ -14,6 +14,7 @@ import { run } from "@ember/runloop";
 import selectKit from "discourse/tests/helpers/select-kit-helper";
 import sinon from "sinon";
 import { toggleCheckDraftPopup } from "discourse/controllers/composer";
+import LinkLookup from "discourse/lib/link-lookup";
 
 acceptance("Composer", function (needs) {
   needs.user();
@@ -934,4 +935,30 @@ acceptance("Composer", function (needs) {
       "it does not unescapes script tags in code blocks"
     );
   });
+
+  test("Shows duplicate_link notice", async function (assert) {
+    await visit("/t/internationalization-localization/280");
+    await click("#topic-footer-buttons .create");
+
+    this.container.lookup("controller:composer").set(
+      "linkLookup",
+      new LinkLookup({
+        "github.com": {
+          domain: "github.com",
+          username: "system",
+          posted_at: "2021-01-01T12:00:00.000Z",
+          post_number: 1,
+        },
+      })
+    );
+
+    await fillIn(".d-editor-input", "[](https://discourse.org)");
+    assert.equal(find(".composer-popup").length, 0);
+
+    await fillIn(".d-editor-input", "[quote][](https://github.com)[/quote]");
+    assert.equal(find(".composer-popup").length, 0);
+
+    await fillIn(".d-editor-input", "[](https://github.com)");
+    assert.equal(find(".composer-popup").length, 1);
+  });
 });